油基钻井液下水泥浆抗污剂的研究与应用

Study and Application of Anti-contamination Agent for Cement Slurry in Wells Drilled with Oil Base Drilling Fluids

针对目前油基钻井液下水泥浆易被污染,固井质量难以保证的问题,运用实验方法结合理论分析,开展了抗污染水泥浆体系的研究。利用人工岩心法证实了油基钻井液对固井质量有较大影响,特别是对二界面胶结强度影响最大。通过实验分析了基础水泥浆被油基钻井液污染后性能的变化,研制出了一种主要成分为烷基酚聚氧乙烯醚的抗污染剂Anti-P。室内实验结果表明,将1%抗污剂Anti-P加入水泥浆中,在水泥浆被少量油基钻井液污染后(小于10%),水泥浆性能不受影响,保证了固井质量。将其在多口井进行应用,效果良好。该成果填补了目前抗污染水泥浆体系的空白,值得进一步研究推广。

Wells drilled with oil base drilling fluid always have poor cementing job quality because of the contamination to the cement slurry by the oil base drilling fluid. Studies on the cement slurries that are resistant to contamination have been conducted using experimental method and theoretical analysis. In laboratory experiments with artificial cores, the effects of oil base drilling fluid on the cementing job quality, especially the effects of oil base drilling fluid to the bonding of the cement sheath and the borehole wall,have been proved. Anti-P（main component being alkylphenolpolyethoxylate）, an anti-contamination agent for cement slurry was developed by studying the change of the properties of base cement slurry before and after being contaminated with oil base drilling fluid. Laboratory studies showed that cement slurry treated with Anti-P can stand the contamination by oil base drilling fluid of less than 10%, the properties of the cement slurry was not affected, and the cementing job quality satisfied the requirements. The application of Anti-P in several wells has gotten good results. This technology has filled the gap of anti-contamination cement slurry and is well worth further study and application.